TEHRAN, Iran — Tensions appear to be mounting again in the Strait of Hormuz, as seen in a video released by the US military Aug. 23. The footage shows four patrol boats operated by Iran’s Islamic Revolutionary Guard Corps (IRGC) approaching a US destroyer in the narrow waterway. US military officials say two of the patrol boats came within 300 yards of the destroyer USS Nitze. A series of similar incidents were reported the following day with one encounter resulting in the US ship firing warning shots. Earlier, on July 12, US media had reported five IRGC speedboats coming within close proximity of a US ship in the Persian Gulf.

The Pentagon has described the actions of the Iranian naval vessels last month as “unsafe and unprofessional.” Iranian Defense Minister Hossein Dehghan, however, defended the movements of the IRGC patrol boats, stating, “Preserving the country’s security at sea and in the Persian Gulf is our responsibility. It is natural that these boats would be continuously monitoring the traffic of foreign vessels in Iran’s territorial waters.” Were the Iranian boats, however, acting in accordance with domestic and international laws?

The United States considers the Strait of Hormuz to be international waters, and as such, an area where its vessels are allowed to move freely, without interference from littoral states. This attitude is evident in the messages transmitted by the US vessels to the Iranian boats. Indeed, the Transit Rights of Passage under the Law of the Sea says that the littoral state, in this case Iran, has no right to interfere in the passage of foreign ships, whether military or civilian. The Iranian government, however, citing a series of legal arguments, rejects this position.

In 1993, Iran approved the Act on the Marine Areas of the Islamic Republic of Iran in the Persian Gulf and the Oman Sea. The statute extends Iran’s sovereignty beyond the “Strait of Hormuz and the Oman Sea, to a belt of sea, adjacent to the baseline, described as the territorial sea.” It also declares that the passage of foreign vessels is subject to the principle of innocent passage so long as it is not prejudicial to good order, peace and security of the Islamic Republic of Iran.